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Seven-level inverter circuit, inverter and control method

A three-level inverter and inverter circuit technology, applied in electrical components, conversion devices for converting AC power input to DC power output, and output power, etc., can solve the problem of unstable neutral point voltage and difficult to control capacitor voltage. Balance, inverter system complexity and other issues, to prevent output level unbalance, simple implementation, and strong practicability

Pending Publication Date: 2021-06-18
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the current research, the multi-level inverter also brings some problems, such as the difficulty of controlling the balance of the capacitor voltage, the instability of the neutral point voltage, and the complexity of the inverter system, etc.

Method used

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  • Seven-level inverter circuit, inverter and control method
  • Seven-level inverter circuit, inverter and control method
  • Seven-level inverter circuit, inverter and control method

Examples

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Embodiment 1

[0046] This embodiment discloses a seven-level inverter circuit, figure 1 It is a topology diagram of a cascaded seven-level inverter, including a T-type three-level inverter and an H-bridge circuit. Each phase of the T-type three-level inverter includes four IGBT tubes, which can output -2E, 0 , 2E three levels, DC side power supply voltage U dc is 4E, the voltage of the two capacitors on the DC side is 2E each, and the voltage of the floating capacitor in the H-bridge circuit is U af , U bf , U cf Both are E, so according to different switching states, the current flows through different paths. Cooperating with the four IGBT tubes of the H-bridge circuit, each phase can output seven levels, and you can get -3E, -2E, -E, 0 respectively. , E, 2E, 3E seven levels. The simulation experiment parameters are set as: U dc =4E=600V, filter inductance L F =10mH, filter resistance R F =0.5Ω, DC side capacitance C d1 =C d2 =1000μF, floating capacitance C a =C b =C c =1000μF,...

Embodiment 2

[0085] The purpose of this embodiment is to provide a two-stage model predictive control method for a seven-level inverter, specifically, the abc three-phase sampling current is transformed by Clark to obtain the current i in the two-phase stationary coordinate system α (k) and i β (k), abc three-phase grid side sampling voltage is transformed by coordinates to obtain the voltage value e in the two-phase stationary coordinate system α (k) and e β (k), the current i is obtained by Lagrangian extrapolation method α (k+1) and i β (k+1), and the model predictive control formula after discretization can calculate the reference voltage value u at the next moment α (k+1) and u β(k+1), through the value function g, the two voltage vectors with the smallest g are calculated as candidate vectors, and then the specific switch state is selected according to the requirements of the midpoint potential balance and the suspension capacitor voltage balance, and finally acts on each switch....

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Abstract

And The invention provides a seven-level inverter circuit, an inverter and a control method. The seven-level inverter circuit comprises a T-type three-level inverter and an H-bridge circuit, the T-type three-level inverter outputs three levels and is cascaded with the H-bridge circuit to realize that each phase outputs seven levels; and three phases of the T-type three-level inverter share two direct current side capacitors, and each phase is provided with a suspension capacitor. According to the technical scheme, only the zero common-mode voltage vector is selected as the candidate vector, so that the common-mode voltage of the inverter is well reduced.

Description

technical field [0001] The disclosure belongs to the technical field of inverter control, and in particular relates to a seven-level inverter circuit, an inverter and a control method. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] Today, when energy is increasingly scarce and the environment is seriously polluted, renewable energy such as wind energy and solar energy has developed rapidly. As the interface between the renewable energy system and the grid, the performance of the grid-connected inverter directly affects the output power quality of the power generation system. [0004] Compared with low-level inverters, multi-level inverters have been widely used in industry in recent years due to their special advantages. The advantages of the multi-level inverter mainly include: its improved output waveform quality is better, it can re...

Claims

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Application Information

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IPC IPC(8): H02M7/5387H02M1/12H02M1/088
CPCH02M7/53871H02M1/12H02M1/088
Inventor 张承慧刘浩李晓艳邢相洋胡顺全任其广
Owner SHANDONG UNIV